Authorities in the central province of Ha Tinh said they are looking into allegations that a unit of Taiwanese firm Formosa buried industrial waste in a private farm with the help of the property's owner.

The scandal came as Formosa Ha Tinh Steel Corp. (FHS) is still struggling with a public relations disaster following mass fish deaths in the central region.

Vo Ta Dinh, director of the provincial Department of Natural Resources and Environment, said Tuesday that authorities had unearthed around 100 tons of muddy waste allegedly disposed of by FHS in a farm.

The farm, which grows mostly banana and cajuput trees, is owned by Le Quang Hoa, the director of state-owned Urban Environment Company in Ky Anh Town.

Dinh said samples of the waste were collected for testing.

Authorities also confiscated equipment used to bury the waste after inspecting the farm on Monday.

According to local police, Hoa’s company signed a contract to transport waste from the construction site of a new FHS steel factory to two licensed waste treatment plants in the province.

The questions that investigators will try to answer are why the waste ended up in Hoa’s farm and whether it is toxic.

Hoa told Thanh Nien the waste was not toxic and that trees could grow on it.

FHS, a subsidiary of Taiwan's Formosa Plastics, has been in hot water over the past two months after an estimated 70 tons of fish were found dead and washed ashore in April in four central Vietnamese provinces Ha Tinh, Quang Binh, Quang Tri and Thua Thien-Hue. It was accused of discharging toxic waste into the sea.

FHS accepted responsibility for the environmental disaster and promised to pay US$500 million in compensation late last month.

Experts believe it will take years, if not decades, before the regional marine environment can fully recover from the toxic spill.